perf(imageproxy): do not set cookies to image proxy so CDNs can cache images (#3332)

CDNs such as Cloudflare bypass their cache if cookies are set in the response.
clearCookies
middleware removes the header before imageproxy serves the image.

server/index.ts

@@ -17,6 +17,7 @@ import WebhookAgent from '@server/lib/notifications/agents/webhook';
 import WebPushAgent from '@server/lib/notifications/agents/webpush';
 import { getSettings } from '@server/lib/settings';
 import logger from '@server/logger';
+import clearCookies from '@server/middleware/clearcookies';
 import routes from '@server/routes';
 import imageproxy from '@server/routes/imageproxy';
 import { getAppVersion } from '@server/utils/appVersion';
@@ -182,7 +183,8 @@ app
     });
     server.use('/api/v1', routes);
 
-    server.use('/imageproxy', imageproxy);
+    // Do not set cookies so CDNs can cache them
+    server.use('/imageproxy', clearCookies, imageproxy);
 
     server.get('*', (req, res) => handle(req, res));
     server.use(

server/middleware/clearcookies.ts

@@ -0,0 +1,6 @@
+const clearCookies: Middleware = (_req, res, next) => {
+  res.removeHeader('Set-Cookie');
+  next();
+};
+
+export default clearCookies;